I find it weird how little fanart we got crossing over kingdom hearts and Doom.
You know because of the fanart we got putting together miis and the characters tied to them.
I mean, at the start it does happen for some time, like what happened with Sans, Cuphead, Shantae and the Final Fantasy costumes. Even Doom Slayer got some fanart early on, with some unsurprisingly putting the Doom Slayer Mii character with Isabelle.
But also unsurprisingly, it's the player characters who get the most attention and lasting power whereas Assist Trophies, Mii Costumes and Spirits are often left behind after an initial start and run. Like it says alot when the Mii Brawler, Swordfighter and Gunner default looks often get more fanart than most of the Mii Costumes.
You will get some of them with more lasting power than others, like Sans, Waluigi and the meme of Shantae's Spirit possessing Samus, back when that Spirit/Character meme got an active start, but lost popularity somewhat quickly with Shantae Samus itself lasting somewhat longer, but without the hype backing ATs, most Mii Costumes and Spirits compared to the player characters, it's not unusual to see them drop in fanart faster than the player characters.